AFAICT there was no such purely DirectShow-based command-line player
yet, which is why I created it. There is e.g. ffplay.exe (which comes
with FFmpeg) which also supports DirectShow, but it has (statically
compiled) 40-60 MB, whereas my dscmd.exe only has 192 kB, since it
doesn't contain any media format/codec parsing code (like libavcodec for
ffmepg/ffplay) at all, but instead only relies on the DirectShow system.
And it also doesn't rely on SDL, but instead uses native Win-API windows
for displaying video in a window.

But it's nevertheless quite powerful, here a couple of features as
unsorted list:

- it allows to build arbitrary DirectShow graphs explicitely

- it allows to load DirectShow filters at runtime, so no registration
(which would require elevated privileges) needed.

- it supports VMR-7, WMR-9 and EVR video renderers (others, like
legacy renderer or Haali only work partially)

- using the LAV (or alternatively FFdshow) filters, it provides the
power of libavcodec etc., so about the same (long) list of supported
container formats and media codecs as ffplay/ffmpeg.

Check out/run the demo batch scripts in folder "demos". Most of them
should run in any recent Windows (e.g. Win 8.x/Win 10.x, 32/64-bit).
Only 3 of them - demo_file_video.bat, demo_file_fullscreen.bat and
demo_url_video.bat - are meant to demonstrate direct video playback
without creating an explicit filter graph, and therefor rely on
appropriate filters registered in the system. If those 3 demos don't
work for you, you can execute "__register_run_as_admin.bat" in folder
"demos/filters" - by running it as admin, as the name suggests - to
register the provided LAV filters, then also those should work.

Final note: in interactive mode (-i), you can switch (toggle) any loaded
video to fullscreen by typing "f" after the video was loaded. But the
commandline argument "-fullscreen" is meant for situations when only
strict fullscreen playback is required and never the desktop should be
shown. Therefor this mode doesn't allow to switch back to non-fullscreen
mode, and therefor also not to quit the player by closing the video
window via close button in its title bar. To quit a player running in
this explicit fullscreen mode, in interactive mode just type "q" or ESC,
otherwise shortcut Alt-F4 always works.